Carboxyl-containing polymers, homopolymers, or copolymers with other vinylidene monomers containing at least one terminal CH.sub.2 &lt; group, of unsaturated polymerizable carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid and the like are useful thickening agents. These polymer acids often are cross-linked with small amounts of cross-linking agents. One class of these polymeric materials are prepared by polymerization of the acid with a free radical catalyst in mineral spirits in a closed vessel or autoclave with stirring.
The carboxyl-containing polymers dispersed in mineral spirits find many applications. However, upon storage, the dispersed polymer generally settles to the lower portion of the container and often is very difficult or impossible to redisperse. Mineral spirit dispersions of carboxyl-containing polymers that are readily redispersed by shaking or simple stirring, even after long periods of storage, are desired.
The patent application of K. E. Burnfield, entitled "Stabilization of Mineral Spirit Dispersions of Carboxyl-Containing Polymers", filed Oct. 24, 1983 and bearing Ser. No. 06/544342,now abandoned, discloses stabilization of the carboxyl containing polymers in mineral spirits by the addition of a glyceryl tris-12-hydroxystearate and/or mixed saturated C.sub.18-36 fatty acid triglycerides. Such dispersions were thought to be stable, however, it was discovered that when these dispersions were transported in 55-gallon drums, the solids settled as a hard cake that was very difficult to redisperse.